Sound-reproducing machine.



S. I. PRESCOTT.

SOUND REPRODUGING MACHINE.

APPLICATION FILED MAR.18, 1909.

965,329, Patented July 26, 1910.

ATTEST \NVENTOR brations.

nnrren I. PRESCOTT, 0F CALEDEE, NEW JERSEY.

To all whom it may concern:

Be it known that I, SYDNEY l. PRESCOTT, a citizen-of the United States,residing at Camden, county of Camden, in the State of New Jersey, haveinvented a new and useful Sound-Reproducing Machine, of which thefollowing is a specification.

This invention relates to improvements in sound reproducing machines.

Heretofore, there have been in use two distinct types of soundreproducing machines, both of which utilized a record of sound vi- Inone type, the stylus operating in connection with the record vibrated adiaphragm which set up corresponding sound impulses. In the other type,the stylus operated a valve which controlled a flow of air underpressure, the sound impulses being enerated in this case by theinterruption 0% the flow of the air. In the diaphragm type of machine,the impulses were produced by compressing the air be tween the diaphragmand a compression surface in close proximity thereto, the impulsesescaping through an outlet port in the coinpression surface. When thediaphragm was moved toward the compression surface, the air in the spacebetween the two was slightly compressed and this resulted in a slightflow of air through the outlet port. When' the diaphragm moved in theopposite direction;

7 that is to say, away from the compression surface, the tendency was tocreate a partial vacuum between the diaphragm and the compressionsurface, and draw back into this space the air which had just beenforced out.

.Thus was produced an area of rarefaction following the area ofcompression. lln view of the fact that the diaphragm exerted a forceduring the rarefaction period equal to the force exerted during thecompression period, what was done during the compres sion eriod waspartially undone during the raref ying period. The result was the partial obliteration of the sharp line of demarcation between thesuccessive areas of courpression and rarefact-ion. The absence of asharp line of demarcation between the area of compression and the areaof rare faction which together form what is commonly known as an airvibration, results in a sound which is more indistinct" than it shouldbe, and the higher the pitch and the greater the volume of the sound,the greater specification of Letters Eatent. Pg ingntgfi J1" rally 2Application filed March 18, 1909.

Serial Ho. 484,237.

is the loss. What is knownas blasting of the tone is partially due tothe act-ion above referred to.

It is one of the objects of this invention to provide means whereby thesharp line of demarcation between the successive areas of compression"and'rarefaction shall not be affected by the means employed forimparting sound impulsesfi A further object of the invention is toprovide means for conducting a continuous flow of air to thesimpulse orcompression surface, so that there will be no tendency of the impulseimparting means to retard the propagation of the successive areas of compression and rarefaction.

Another object of the invention is to provide means for conductingacontinuous flow of air to and across the compression surface in aplurality of streams %that there will be no uneven action while soundimpulses are imparted to the air covering the compression surface.

With these and other objects,,not specifically mentioned, in View, theinvention consists in certain constructions and combinations which willhereinafter be fully described and then specifically pointed out in theclaims hereunto appended.

In the accompanying drawings which form 9. art of this specification,and in which li e characters of reference indicate the same parts,Figure 1 is a side elevation of a device constructed in accordance withthe invention; Fig. 2 is a plan view of the structure illustrated inFig. 1; Fig. 3 is a section on the line 33 of Fi 2; Fig. 4 is a sectionon the line d l of Fig. 1; and Fig. 5 is a detailed View.

In sound reproducing machines when sound impulses are imparted to theair, it is desirable that the line of demarcation be tween thesuccessive areas of coin ression and rarefaction be kept sharply efined,particularly when notes of high pitch or eat volume are reproduced, forunless this is done there is danger of the note being blasted. incarrying the present invention into efiect, therefore, means areprovided for maintaining the sharp line of demarcat on between thesuccessive areas of compression and rarefaction, before difi'usion inthe atmosphere, and this means may vary within wide limits. While insome constructions other means may be employed for this purpose, in thebest constructions the desired result will be effected by conducting acontinuous flow of air to the means for imparting sound impulses, sothat there will be no .ing compression surface, both of which may varywithin wide limits. When a compression surface is used, a continuousflow of air will be conducted to and across it, preferably in aplurality of streams converging radially toward a common center, so thatthe impulse imparted to, the air covering the compression surface willbe conducted evenly to the common center. As shown, there is provided adiaphragm 1 mounted, in a manner well known in the art, in a sound box2. In closeproximity to the diaphragm 1 is a compression surface 3. Thecompression surface 3 is provided with a series of radial channels 4crossing its face, these channels forming means for conducting acontinuous flow of air to and across the surface. In the device selectedto illustrate the invention, the compression surface is flat andcircular, althou h itwill be readily understood that other orms may, insome constructions, be used. The compression surface is provided with anoutlet port 5 which is, or maybe, centrally located, and the channels 4,before referred to, are in communication with this outlet port. When thediaphragm moves toward the compression surface, the impulse set upescapes through the outlet port 5 in the same manner as it does in manysound boxes well known in the I art; that is to say, the air compressedbetween the diaphragm and the compression surface moves outwardlythrough the outlet port 5. When the diaphragm moves away from thecompression surface, a larger space is formed between it and thecompression surface, and this space must be filled with air. Air isconducted through .the channels 4, before referred to, to take the placeof the air expelled throu h the outlet port 5, so that there is no re exaction or partial obliteration of the sharp line of demarcation betweenan area of compression which has just passed through the outlet port 5and the following area of rarefactionu In order to supply a continuousflow of air to the channels 4, there is provided a series, of b passes6, one for each channel, around t e gaskets 7 and edge of thediaphragm1, and in communication with a chamber 8 within which thediaphragm is mounted. These by-passes continuous flow of air from theopposite side provide means for conducting a of the diaphra to thecompression surface. It will e readily understood that since thedistance'from the diaphragm to the base of the channels 4 is very muchgreater than the distance from the diaphragm to the impulse field orcompression surface, that there will be no interruption to thecontinuous flow of the airthrough the channels for there will be littleor no compression of the air within the channels. The impulse set upbetween the diaphragm and compression surface will, however, be impartedto the air within the channels.

The continuously flowing air may be obtained from any suitabie source ofsupply. In the device selected to'illustrate the invention, the air willcome from a suitable source of supply, not shown, through a pipe 9mounted on the under side of a sound conducting tube 10 forming a partof the reproducing apparatus, and the construction of which is wellknown in the art. The air pipe 9 is in communication with a channel 11formed in a T-coupling 12 on the end of the sound conducting tube 10.The channel 11 is in turn in communication with a bent tube 13 one endof which is connected with the sound box 2, its interior being incommunication with the chamber 8. The outlet port 5, before referred to,is in communication with a bent tube 14, one end of which is incommunication with a chamiel 15 formed in the T-coupling 12 and whichdischarges into the interior of the sound conducting arm 10. A moredetailed description of this part of the device is deemed unnecessary toan understanding of the invention and is, therefore, omitted in theinterest of brevity and clearness. The diaphragm 1 is connected in theusual manner with a stylus 16 which operates in conjunction with arecord disk 17. A detailed description of the connections between thephragm 1 and the stylus 16, and of the record 17 and its operatingmechanism, not being necessary to an understanding of the presentinvention, is omitted in the interest of brevity and clearness.

In view of the foregoing, a detailed de scription of the operation ofthe device is considered unnecessary.

Changes and variations may be made in the structure by which theinvention is carried into effect. The invention, therefore, is not to berestricted to the precise details of the structure shown and described.

What is claimed is:

1. In a sound reproducing machine, the combination with acompression-surface, of means for conducting a continuous flow of air toand across said surface in a plurality of streams, substantiallyasdescribed.

2. In a sound reproducing machine, the combination with a compressionsurface, of means for conductingva continuous flow of dia- combinationwith air to and across said surface in a plurality of converging streamssubstantially as described.

3. In asonnd reproducing machine, the combination with a circularcompression surface, of means for conducting a continuous flow of air toand radially across said surface in a plurality of streams,substantially as described.

4. In a sound reproducing machine, the combination with a circularcompression surface having a plurality of radial channels, of means forconducting a continuous flow of air to and through said channels,substantially as described.

5. In a sound reproducing machine, the combination with a compressionsurface, of means for conductin a continuous flow of air to and acrosssaid surface in a plurality of streams, and means for imparting soundimpulses to the air covering the compression surface, substantially asdescribed.

6. In a sound reproducing machine, the combination with a compressionsurface, of

means for conducting a continuous flow of air to and across said surfacein a plurality of converging streams, and means for imparting soundimpulses to the aircovering the compression surface, substantially asdescribed.

7. In a sound reproducing machine, the combination with a circularcompression surface, of means for conducting a continuous flow of air toand radially across said surface in a plurality of streams, and meansfor imparting sound impulses to the air covering the compressionsurface,substantially as described.

8. In a sound reproducing machine, the a circular compression surfacehaving a plurality of radialchannels, of means for conducting acontinuous flow of air to and through said channels, and means forimparting sound impulses to the air covering the compression surface,substantially as described.

9. In a sound reproducing machine, the combination with a compressionsurface, of means for conducting acontinuous flow of air to and acrosssaid surface in a plurality of streams, and a diaphragm for impartingsound impulses to the air covering the compression surface,substantially as described.

10. In a sound reproducing machine, the combination with a compressionsurface, of means for conducting a continuous flow of air to and acrosssaid surface in a plurality of converging streams, and a diaphragm forimparting sound impulses to the air covering the compression surface,substantially as described.

11. In a. sound reproducing machine, the

combination with a circular compression surface, of means for conductinga continuous flow of air to and radially across said surface in,plurality of streams, and a diaphragm for imparting sound impulses tothe air covering the compression surface, substantially as described.

12. In a sound reproducing machine, the combination with a circularcompression surface having a plurality of radial channels, of means forconducting a continuous flow of air to and through said channels, and adiaphragm for imparting sound impulses to the air covering thecompression surface, substantially as described.

13. In a sound reproducing machine, the combination with a chamber, ofadiaphragm within the chamber, a compression surface on one side of thediaphragm, and means for conducting a continuous flow of air from theopposite side of the diaphragm to the compression surface, substantiallyas described.

11. In a sound reproducing machine, the combination with a chamber, ofadiaphragm within the chamber, a compression surface on one side of thediaphragm, and means for conducting a continuous flow of air in aplurality of streams from the oppositeside of the diaphragm to thecompression surface, substantially as described.

15. In a sound reproducing machine, the combination with a compressionsurface, of means for conducting a continuous flow of air to thesurface, a diaphra ing sound impulses to the air covering thecompression surface, the compression surface being provided with an.outlet port for the sound, substantially as described.

16. In a sound reproducing machine, the

I combination with a compression surface, of

means for conducting a continuous flow of .-air to the surface, adiaphragm for imparting sound impulses to the air covering thecompression surface, the compression surface being provided with acentrally located outlet port for the sound, substantially as described.

17. In a sound reproducing machine, the, combination with a compressionsurface having an outlet port for the sound, of means for conducting acontinuous flow of air to and across the compression surface to theport, and means for imparting sound impulses to the air covering thecompression surface, substantially as described.

18. In a sound reproducing machine, the combination with a compressionsurface having a centrally located outlet port for the sound, of meansfor conducting a continuous flow of air to and across the compressionsurface to the port, and means for imparting sound impulses to the aircovering the compression surface, substantially as described.

19. In a sound reproducing machine, the combination with a compressionsurface having an outlet port for the sound, of

for impartmeans for conducting a continuous flow of air to and acrossthe compression surface to the port, and a diaphragm imparting soundimpulses to the air covering the compression surface, substantially asdescribed.

20. In a sound reproducing machine, the combination with a compressionsurface having a centrally located outlet port for the sound, of'meansfor conducting a continuous flow of air to and across the compressionsurface to the port, and a diaphragm imparting sound impulses to the aircovering the compression surface, substantially as described. 4

21. In a sound reproducing machine, the combination with a chamber, of adiaphragm within the chamber, a compression surface on one side of thediaphragm, and a bypass for conducting a continuous flow of air from theopposite side of the diaphragm to the compression-surface, substantiallyas described.

22. In a sound reproducing machine, the combination with a chamber, of adiaphragm within the chamber, a compression surface on one side of thediaphragm, and a plurality of by-passes for conducting a continuous flowof air -in a plurality of streams from the opposite side of thediaphragm to the compression surface, substantially as described.

23. In a sound reproducing machine, the combination with a chamber, of adiaphragm within the chamber, a compression surface on one side of thediaphragm and having a plurality of radial channels, and a plurality ofbyasses for conducting a continuous flow 0 air in a plurality of streamsfrom the opposite side of the diaphragm to the channels in the comression surface, substantially as describe In testimony whereof, I havesigned my name to this specification in the presence of two subscribinwitnesses.

SYDNEY I. PRESCOTT. Witnesses:

FRANK BLMIDDLETON, Jr.,

ETHEL M. WHITEHEAD.

